Fluoropolymers, such as poly(vinylidene) fluoride (PVDF), have excellent strengths, robustness and rigidity, and outstanding chemical stability. Moreover, fluoropolymers have good dielectric constants and contact angles of about 90 degrees, such that they are suitable to be used as protective layers and insulating layers.
Usually, polymers easily age under irradiation of ultraviolet rays, and are prone to have reduced lives as they are exposed to heat and contaminants. By the addition of a UV absorber, a UV stabilizer or an inorganic particle, the life of a polymer can be extended. In a composite material product, inorganic particles (such as BaTiO3 or TiO2) with a high dielectric constant, a fluoropolymer and a solvent are mixed to increase the dielectric property of the blended material. However, the transmittance of the composite material is yet to be improved.
On the other hand, if a transparent non-crystalline polymer (such as PMMA and PEO) and a fluoropolymer are mixed to form a composite material. Although the optical property of the composite material is improved, the dielectric property of the composite material is significantly decreased as the proportion of the transparent non-crystalline polymer added is increased. Moreover, there are also reports on the addition of a polymer (such as PS or PPO) with a higher resistance and a lower dielectric loss for increasing the dielectric strength, rather than optical characteristics, of a composite material.
It is an important issue to develop a coating layer based on a fluoropolymer with high a transmittance.